Cordless telephone system

Abstract

A cordless telephone system includes a connector connected to a subscriber telephone line and at least one radio telephone set through a radio channel to establish or hold a communication channel between the ratio telephone set and a subscriber. The connector includes a control unit incorporating a timer. The control unit sets the system in a self hold state in which the radio channel is kept connected or a complete hold state in which the radio channel is disconnected on the basis of a hold signal from the radio telephone set, the presence/absence of a radio reception signal within a predetermined period of time preset in the timer, and the type of reception signal.

What is claimed is: 
     
       1. A cordless telephone system comprising at least one radio telephone set, a subscriber line connected through a telephone exchanger to a subscriber telephone set, and connector means, connected to said at least one radio telephone set through a radio channel and to said subscriber line and having a function for establishing a communication channel between said at least one radio telephone set and said subscriber telephone set and a function for holding said communication channel in response to a hold signal from said at least one radio telephone set, wherein said connector means comprises: first hold state setting means for setting said communication channel in a first hold state without disconnecting said radio channel in response to the hold signal received upon establishment of said communication channel;   first determining means for determining the presence/absence of a radio reception signal within a first predetermined period of time after the first hold state is initiated;   hold state releasing means for releasing the first hold state and reconnecting the communication channel when the radio reception signal received at first within the first predetermined priod of time is the hold signal in accordance with a determination result of said first determining means;   second hold state setting means for disconnecting said radio channel and setting said communication channel in a second hold state when the radio reception signal received at first within the first predetermined period of time is an on-hook signal or the radio reception signal is not received within the first predetermined period of time, in accordance with the determination result of said first determining means;   second determining means for determining the presence/absence of the radio reception signal within a second predetermined period of time after the second hold state is initiated;   hold state changing means for changing the second hold state to the first hold state when the radio reception signal received within the second predetermined period of time is an off-hook signal, in accordance with a determination result of said second determining means; and   circuit control means for forcibly disconnecting said communication channel and setting said communication channel in a stand-by state when the radio reception signal is not received within the second predetermined period of time, in accordance with the determination result of said second determining means.   
     
     
       2. A cordless telephone system comprising at least one radio telephone set, a subscriber line connected through a telephone exchanger to a subscriber telephone set, and connector means, connected to said at least one radio telephone set through a radio channel and to said subscriber line and having a function for establishing a communication channel between said at least one radio telephone set and said subscriber telephone set and a function for holding said communication channel in response to a hold signal from said at least one radio telephone set, wherein said connector means comprises   radio transmitting/receiving means connected to said radio channel,   control means, incorporating a timer, for controlling operations of said connector means in response to various signals received from said at least one radio telephone set through said radio transmitting/receiving means,   holding tone generating means, controlled by said control means, for generating a holding tone signal representing a hold state, and   switching means, controlled by said control means, for connecting said subscriber line and said radio transmitting/receiving means with each other to set a talking state when said communication channel is established, and for connecting an output from said holding tone generating means to said subscriber line and said radio transmitting/receiving means in the hold state; and   wherein said control means controls   to cause said switching means to disconnect said subscriber line from said radio transmitting/receiving means in response to the hold signal from said at least one radio telephone set during establishment of said communication channel and at the same time cause said holding tone generating means to supply an output signal to said subscriber line and said radio transmitting/receiving means,   to set a first predetermined time to said timer and cause said timer to start,   to keep connecting said radio channel to said radio transmitting/receiving means, thereby initiating a first hold state,   to switch said switching means to a talk position to release the hold state when a radio reception signal received at first within the first predetermined period of time after initiation of the first hold state is the hold signal,   to disconnect said radio channel to set a second hold state when the radio reception signal received at first within the predetermined period of time is an on-hook signal or the radio reception signal is not received within the first predetermined period of time,   to set a second predetermined time in said timer and cause said timer to start,   to change the second hold state to the first hold state in response to a first off-hook signal received within the second predetermined period of time in the second hold state, and   to inhibit a transmission function of said radio transmitting/receiving means and set said radio transmitting/receiving means in a stand-by state when the radio reception signal is not received within the second predetermined period of time.   
     
     
       3. A system according to claim 2, wherein said connector means comprises display means, connected to said control means, for displaying the first and second hold states. 
     
     
       4. A system according to claim 2, wherein said radio telephone set comprises operation means for generating said hold signal, said on-hook signal, and said off-hook signal. 
     
     
       5. A system according to claim 2, wherein said connector means further comprises a handset connected to said subscriber line and said radio transmitting/receiving means respectively through said switching means and said control means. 
     
     
       6. A system according to claim 4, wherein said operation means comprises a hold button for generating said hold signal, a talk completion button for generating said on-hook signal, and a talk button for generating said off-hook signal.